Types of Braking System in Automobile

Main Ideas

How Braking Works

A moving car has kinetic energy. Brakes slow or stop it by using friction to convert that energy into heat.

In a typical hydraulic system, pressing the brake pedal moves a piston in the master cylinder. Hydraulic fluid carries and multiplies the force through brake lines to the wheel brakes. The tires then rely on friction to transfer the braking force to the road.

Brakes are essential to vehicle safety, and understanding how they work can help drivers recognize when a problem may have developed.

Brake Placement and Types

The video focuses on two common wheel-brake designs: disc brakes and drum brakes.

Many cars use disc brakes at the front and drum brakes at the rear. Because braking shifts weight toward the front wheels, front brakes generally handle more of the stopping work and heat. Some vehicles—particularly higher-performance or more expensive models—use disc brakes on all four wheels.

Regenerative braking in hybrid and electric vehicles can reduce wear on conventional brakes.

Drum Brakes

How They Work

A rotating drum turns with the wheel. When the brake is applied, a hydraulic cylinder pushes friction-lined shoes outward against the drum’s inner surface. The resulting friction slows the wheel.

Drum brakes can also be designed as clasp, pinch-drum, or band brakes, though the standard arrangement presses shoes against the inside of the drum.

Advantages

• They are often economical and can produce substantial braking force.
• Their large friction-contact area can help the shoes last longer than similarly sized disc pads.
• They can be well suited to rear-wheel applications, where braking demands and heat are generally lower.
• They can incorporate a parking brake relatively simply, and return springs help pull the shoes away from the drum when released.
• Their enclosed design can keep more wear particles contained.

Limitations and Failure Concerns

• Drums can retain heat. Heavy or repeated braking may cause them to expand or distort, potentially leading to vibration and brake fade.
• Heat can reduce the friction material’s effectiveness. Severe overheating may glaze the surface or cause brake fluid to vaporize, reducing braking pressure.
• Rust or damp, cold conditions can sometimes make drum brakes “grab” rather than release smoothly.
• Drum designs have more parts than disc systems, making service more involved and creating more possible failure points. Broken springs or adjusters can cause unintended brake application or even wheel lock.
• Worn or damaged drums are generally harder to machine than rotors and may need replacement. The video emphasizes replacing relevant springs and clips when servicing shoes.

Disc Brakes

How They Work

A rotor (disc) rotates with the wheel. A caliper presses brake pads against both sides of the rotor, creating friction and slowing or stopping the wheel.

Calipers may be:

• Fixed, with pistons on both sides of the rotor.
• Floating or sliding, where movement of the caliper brings the outer pad into contact.

Floating calipers can stick if their guides become dirty, corroded, or poorly lubricated. This may cause drag, excess heat, uneven pad wear, reduced fuel efficiency, or vibration.

Design and Maintenance

Rotors are commonly made of cast iron. Some are ventilated, with internal passages to help dissipate heat. Others have drilled holes or slots intended to help manage heat, water, gas, or debris.

Two-piece rotors separate the central mounting section from the outer friction ring. The video describes potential benefits such as reduced unsprung weight and improved handling of heat expansion, while noting that floating designs can rattle or collect debris.

Brake pads are made from high-friction materials and wear over time. Some vehicles use squealing tabs, electrical contacts, or sensors to indicate when replacement is needed. The video also cautions against inhaling brake dust, including dust from newer pad materials.

Comparison with Drum Brakes

Disc brakes generally cool more readily, recover more quickly after getting wet, and are less prone to heat-related fade. Their braking force tends to respond more directly to applied pressure, giving the driver a more predictable feel.

Drum brakes may be less expensive and effective in rear applications, but their heat retention and mechanical complexity are important trade-offs.

Historical Context

The video briefly traces disc-brake development from early designs in the 1890s and early 20th century to wider adoption after the Second World War. Racing helped demonstrate the advantages of disc brakes, particularly during repeated high-speed braking, and mass production expanded in the 1950s.

Speakers and Sources Featured

One instructional narrator provides the explanation. No individual speaker is identified by name.